Knock Prediction using Multidimensional Modeling

Two and three-dimensional test cases were simulated using a detailed kinetic mechanism for methane combustion as a subset for di-methyl ether. A generic piston-bowl assembly for the compression and expansion strokes is utilized at 1500 RPM. A fine grid was used for the 2-D simulations and a rather coarse grid was used for the 3-D calculations together with a k-ε subgrid-scale turbulence model and a partially stirred reactor model with three time scales. Pressure fluctuations were captured some time after the ignition started which are indications of knock occurence. Detailed analysis of the pressure data showed that knock was present in the simulations and exhibited similar characteristics to the ones observed in experiments.